Tiered link building boosts your website’s authority by using multiple layers...

https://www.primary-bookmarks.win/tiered-link-building-helps-you-build-a-strong-backlink-profile-by-layering

Tiered link building boosts your website’s authority by using multiple layers of backlinks. Tier 1 links point directly to your site, while Tier 2 links support those Tier 1 sources